1. Field of the Invention
This invention relates to the apparatus for cleaning sewer lines, pipe lines, and closed chambers and/or conduits in which water is jetted into the conduits at high pressures and in which a partial vacuum is applied for removal of liquids and solids from the conduits.
2. Description of the Prior Art
It is well known to provide a mobile sewer cleaning unit having a reservoir for a large supply of water, and water-handling components, including a hose reel, a hose normally coiled thereon, and a high pressure pump suitably connected between the reservoir and the hose to deliver water to the hose at high pressure. Such a unit is shown in U.S. Pat. No. 3,570,526, issued to Fisco. A nozzle, which is typically attached to the free end of the hose, reverses the direction of the high pressure water in such a way as to develop a reaction force which pulls the hose into the sewer line from the hose reel. It is also conventional practice to provide a drive means for the pump, including an internal combustion engine, the water handling components and the drive means usually being mounted upon a rear platform of a truck or on the bed of a trailer.
It is also well known to provide sewer cleaning units with means for collecting the debris flushed from the sewer line by the high pressure water system. Such debris collecting means typically include a receptacle or tank for storing debris, a conduit extending from the receptacle, an intake tube at the end of the conduit to be lowered into the sewer or other chamber from which the debris is removed, and means for creating a suction force at the intake tube to suck the debris through the conduit and into the receptacle.
The suction creating means used in sewer cleaning units are generally either air conveyance systems or vacuum systems. Air conveyance systems for picking up debris from the sewer pipes and similar chambers are well known, such as that shown in U.S. Pat. No. 3,568,589, issued to Shaddock. Such units use a large fan or compressor to create an air flow in the conduit, which carries debris to a receiving tank. In contrast to these air conveyance systems, vacuum systems utilize a vacuum pump to create a partial vacuum in a collecting tank. With this vacuum, solid and liquid material in the sewer pipe or chamber is sucked through the conduit into the tank. In general, sewer cleaning units using vacuum systems have advantages over those using air conveyance systems. Air conveyance units use an open exhaust system for their fan or compressor. When the debris tank is overfilled, contaminated water is picked up into the air system and discharged into the atmosphere, polluting the air and damaging any objects which are sprayed. In contrast, vacuum units use a completely sealed system. When the tank becomes completely full, an automatic check valve system may be used to cut off the vacuum pump to prevent discharge of the contaminated material. Furthermore, vacuum units, by reason of the high suction created in the tank, are capable of collecting both liquid and solid material. The air movement created by the air conveyance system is capable of drawing with it solid particulate debris, but it is limited in drawing up large amounts of liquid. If water in the sewer covers the intake tube on an air conveyance unit, it will cut down the suction capability of the unit. On the other hand, vacuum systems are especially adapted to pick up liquids, since the end of the intake should be sealed in order to maintain a vacuum in the system, and this seal is usually accomplished by submerging the end of the intake tube below the water in the sewer chamber.
Heretofore, cleaning of catch basins and flushing of sewer pipes has often required the use of two separate vehicles. A first vehicle with the hose reel mounted on the rear end was positioned at the manhole and a high pressure hose fitted with a jet nozzle was introduced into the sewer. Water from a tank on the vehicle was pumped through the hose at high pressure to drive the hose through the pipe against the water flow. Debris flushed from the sewer pipe was then sucked out of the catch basin by a second vehicle, which comprised a debris holding tank and a conduit which was lowered into the sewer or other chamber from which the debris was removed. This multiple vehicle system duplicated personnel, and the equipment was difficult to handle.
The debris holding tank has sometimes been mounted on a trailer which is attached to the rear of the truck unit which contains the water tank and the hose unit. In operation, the operator positions himself between the trailer and the rear of the truck and operates the hose unit and simultaneously attempts to operate the unit on the trailer. The operation of two separate units on separately mounted vehicles is cumbersome, difficult, and sometimes dangerous. It is also expensive to provide a separate trailer which duplicates many of the elements of the truck-mounted tanks, such as chassis, frame, and power means as well as the hitching and unhitching mechanisms.
It has been proposed to mount the debris holding tank directly on the truck chassis with the water tank. The debris holding tank would thus be mounted in front of the water reservior and hose unit. However, this arrangement presents problems of weight distribution which may require a pair of axles on the rear of the truck chassis to handle the increased weight loads. In addition, if a boom were mounted on top of the debris holding tank, the boom must extend entirely across the water tank and the hose reel unit to the rear of the vehicle, and this presents several problems. An extremely long horizontally extending boom is more likely to clog during operation and is more unstable due to the long cantilever.